* {
    margin: 0;
    padding: 0;
}

button {
    width: 70px;
    height: 40px;
    background: #308859;
    margin-right: 8px;
    border-radius: 8px;
}

#addNewStudentBtn {
    width: 100px;
}

/*input{*/
/*width: 150px;*/
/*height: 30px;*/
/*}*/

.addNewStudentOper {
    padding: 10px;
}

td {
    text-align: center;
    border-top: 0;
    border-left: 0;
}

tr:hover {
    background: linear-gradient(#afafaf, #cde4da);
}

.addNewStudentInformationShowUpdateBtn {
    background-color: #308859;
}

.addNewStudentInformationShowCancelBtn {
    background-color: #dd470f;
}

table td button {
    height: 20px;
    width: 40px;
    margin: 5px;
    color: white;
}

#selectByDepartment, #selectByBatch, .addNewStudentUpdate {
    width: 150px;
    height: 30px;
}

.addNewStudentUpdate {
    margin: 10px;
}

.addNewStudentInformationShowUpdateBtn, .addNewStudentInformationShowCancelBtn {
    height: 20px;
    width: 40px;
    margin-right: 8px;
}

.addNewStudentInformationShowUpdate {
    display: none;
    /*border:1em solid #3366FF;*/
    height: 80%;
    width: 40%;
    position: absolute; /*让节点脱离文档流,我的理解就是,从页面上浮出来,不再按照文档其它内容布局*/
    top: 8%; /*节点脱离了文档流,如果设置位置需要用top和left,right,bottom定位*/
    left: 30%;
    z-index: 2; /*个人理解为层级关系,由于这个节点要在顶部显示,所以这个值比其余节点的都大*/
    background: #fffef2;
    border: 1px solid #000;
    overflow: auto;
    text-align: center;
}

#over {
    width: 100%;
    height: 100%;
    opacity: 0.8; /*设置背景色透明度,1为完全不透明,IE需要使用filter:alpha(opacity=80);*/
    filter: alpha(opacity=80);
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
    background: silver;
}

select {
    width: 150px;
    height: 30px;
}

.addNewStudentInfo {
    display: none;
}